Memory Cues Research Articles

Binding among select episodic elements is altered via active short-term retrieval.

Of the many elements that comprise an episode, are any disproportionately bound to the others? We tested whether active short-term retrieval selectively increases binding. Individual objects from multiobject displays were retrieved after brief delays. Memory was later tested for the other objects. Cueing with actively retrieved objects facilitated memory of associated objects, which was associated with unique patterns of viewing behavior during study and enhanced ERP correlates of retrieval during test, relative to other reminder cues that were not actively retrieved. Active short-term retrieval therefore enhanced binding of retrieved elements with others, thus creating powerful memory cues for entire episodes.

L-type Ca²⁺ channel blockade with antihypertensive medication disrupts VTA synaptic plasticity and drug-associated contextual memory.

Drug addiction is driven, in part, by powerful and enduring memories of sensory cues associated with drug intake. As such, relapse to drug use during abstinence is frequently triggered by an encounter with drug-associated cues, including the drug itself. L-type Ca2+ channels (LTCCs) are known to regulate different forms of synaptic plasticity, the major neural substrate for learning and memory, in various brain areas. Long-term potentiation (LTP) of NMDA receptor (NMDAR)-mediated glutamatergic transmission in the ventral tegmental area (VTA) may contribute to the increased motivational valence of drug-associated cues triggering relapse. In this study, using rat brain slices, we found that isradipine, a general LTCC antagonist used as antihypertensive medication, not only blocks the induction of NMDAR LTP but also promotes the reversal of previously induced LTP in the VTA. In behaving rats, isradipine injected into the VTA suppressed the acquisition of cocaine-paired contextual cue memory assessed using a conditioned place preference (CPP) paradigm. Furthermore, administration of isradipine or a CaV1.3 subtype-selective LTCC antagonist (systemic or intra-VTA) before a single extinction or reinstatement session, while having no immediate effect at the time of administration, abolished previously acquired cocaine and alcohol (ethanol) CPP on subsequent days. Notably, CPP thus extinguished cannot be reinstated by drug re-exposure, even after 2 weeks of withdrawal. These results suggest that LTCC blockade during exposure to drug-associated cues may cause unlearning of the increased valence of those cues, presumably via reversal of glutamatergic synaptic plasticity in the VTA.

Structural constraints on pronoun binding and coreference: evidence from eye movements during reading.

A number of recent studies have investigated how syntactic and non-syntactic constraints combine to cue memory retrieval during anaphora resolution. In this paper we investigate how syntactic constraints and gender congruence interact to guide memory retrieval during the resolution of subject pronouns. Subject pronouns are always technically ambiguous, and the application of syntactic constraints on their interpretation depends on properties of the antecedent that is to be retrieved. While pronouns can freely corefer with non-quantified referential antecedents, linking a pronoun to a quantified antecedent is only possible in certain syntactic configurations via variable binding. We report the results from a judgment task and three online reading comprehension experiments investigating pronoun resolution with quantified and non-quantified antecedents. Results from both the judgment task and participants' eye movements during reading indicate that comprehenders freely allow pronouns to corefer with non-quantified antecedents, but that retrieval of quantified antecedents is restricted to specific syntactic environments. We interpret our findings as indicating that syntactic constraints constitute highly weighted cues to memory retrieval during anaphora resolution.

The apolitics of memory: Remembering military service under Pinochet through and alongside transitional justice, truth, and reconciliation

Approximately 370,000 young men served as conscripted soldiers during the Pinochet dictatorship. Recruits were at times complicit in, witnesses to, or victims of human rights abuses committed under military rule. Memory of conscription for a long time was hidden behind silence maintained by fear, confusion, shame, anger, alcohol, and drugs. In the mid 2000s, however, ex-conscripts began to gather into groups that functioned first as support networks, and later as advocacy organizations pushing for recognition as victims and for reparations. By 2013, nearly 100,000 former recruits had mobilized. This article historicizes the conscript memory narrative of victimhood that emerged with the ex-conscript movement of the early twenty-first century. It examines the relationship between ex-conscripts’ memory of military rule, transitional justice, and the state-led truth and reconciliation process. Chile’s “politics of memory” provided catalysts and cues for ex-conscript memory, but neither of the competing shared memory frameworks have been unable to accommodate the former recruits’ sense of victimhood. Ex-conscript memory is not bound by a common political identity or interpretation of the 1973 coup or the 17 years of military rule. The “apolitics of memory” have instead ensured that ex-conscripts remember military service under Pinochet not within but rather alongside the country’s politicized memoryscape.

Proustian Products are Preferred: The Relationship Between Odor-Evoked Memory and Product Evaluation

The Proustian memory effect—that fragrances elicit more emotional and evocative memories than other memory cues—is well established. Fragrances also potentiate a variety of psychological states from moods to motivated behavior. Consumer research has shown that pleasant, product-congruent scents enhance product appeal, that products with greater emotional and cognitive involvement are perceived more positively, and that scent can increase recall for product information. However, the effect of Proustian memories on product perception has never been examined. The aim of the present study was to address this issue. An extensive pilot test in which the methods for the main experiment were established was first conducted. The main experiment then tested how a product (body lotion) that varied in fragrance pleasantness and Proustian memory potency was perceived. Data analyses from a nationwide study showed that if the lotion fragrance was perceived as very pleasant, and it evoked potent personal emotional memories, that lotion was liked better and judged to be superior on a variety of functional and emotional attributes than the same lotion whose scent was perceived as equally pleasant but was not experienced as evocative. Our findings demonstrate that it is the personal potency of Proustian memories evoked by a product’s fragrance, more than the hedonic qualities of the scent per se, that drives product perception and has important implications for the development of scented products.

Free and cued memory in relation to biomarker-defined abnormalities in clinically normal older adults and those at risk for Alzheimer’s disease

ObjectivesFurthering our understanding of the relationship between amyloidosis (Aβ), neurodegeneration (ND), and cognition is imperative for early identification and early intervention of Alzheimer's disease (AD). However, the subtle cognitive decline differentially associated with each biomarker-defined stage of preclinical AD has yet to be fully characterized. Recent work indicates that different components of memory performance (free and cued recall) may be differentially specific to memory decline in prodromal AD. We sought to examine the relationship between free and cued recall paradigms, in addition to global composites of memory, executive functioning, and processing speed in relation to stages of preclinical AD. MethodsA total of 260 clinically normal (CN) older adults (CDR=0) from the Harvard Aging Brain study were grouped according to preclinical AD stages including Stage 0 (Aβ-/ND-), Stage 1 (Aβ+/ND-), Stage 2 (Aβ+/ND+), and suspected non-Alzheimer’s associated pathology (SNAP; Aβ-/ND+). General linear models controlling for age, sex, and education were used to assess for stage-based performance differences on cognitive composites of executive functioning, processing speed, and memory in addition to free and cued delayed recall on the Selective Reminding Test (SRT) and Memory Capacity Test (MCT). ResultsGlobal memory performance differed between preclinical stages with Stage 2 performing worse compared with Stage 0. When examining free and cued paradigms by memory test, only the MCT (and not the SRT) revealed group differences. More specifically, Stage 1 was associated with decrements in free recall compared with Stage 0 while Stage 2 was associated with decrements in both free and cued recall. There was a trend for the SNAP group to perform worse on free recall compared with Stage 0. Finally, there was no association between preclinical stage and global composites of executive functioning or processing speed. ConclusionsClinically normal older adults with underlying evidence of amyloidosis and neurodegeneration exhibit subtle, yet measurable differences in memory performance, but only on a challenging associative test. The sensitivity of free vs. cued memory paradigms may be dependent on preclinical stage such that reduced free recall is associated with amyloidosis alone (Stage 1) while a decline in cued recall may represent progression to amyloidosis and neurodegeneration (Stage 2). These findings may have practical applications for clinical assessment and clinical trial design.

Toward an understanding of motivational influences on prospective memory using value-added intentions.

This study examined value-added intentions by manipulating the cognitive frame associated with monetary contingencies for detecting prospective memory (PM) cues. We associated a loss-frame with a monetary punishment for failing to respond to cues and a gain-frame with a monetary reward for remembering to respond to cues and compared those frames to a no-frame control condition with no contingency linked to performance. Across two experiments, we find increased PM performance for participants in the loss-frame (Experiments 1 and 2) and in the gain-frame (Experiment 2) conditions relative to the no-frame condition. This value-related improvement in PM was not accompanied by a significant increase in cue monitoring as measured by intention-induced interference to an ongoing task and recognition memory for ongoing-task items. The few previous studies investigating motivational PM showed mixed results regarding whether PM improves due to incentives or not. Our results provide further evidence that, under some experimental conditions, PM improves with rewards and that the benefit generalizes to penalizing performance. The results have both practical implications and theoretical implications for motivation models of PM.

PhotoPrev: Unifying Context and Content Cues to Enhance Personal Photo Revisitation

Personal photo revisitation on smart phones is a common yet uneasy task for users due to the large volume of photos taken in daily life. Inspired by the human memory and its natural recall characteristics, we build a personal photo revisitation tool, PhotoPrev, to facilitate users to revisit previous photos through associated memory cues. To mimic users’ episodic memory recall, we present a way to automatically generate an abundance of related contextual metadata (e.g., weather, temperature) and organize them as context lattices for each photo in a life cycle. Meanwhile, photo content (e.g., object, text) is extracted and managed in a weighted term list, which corresponds to semantic memory. A threshold algorithm based photo revisitation framework for context- and content-based keyword search on a personal photo collection, together with a user feedback mechanism, is also given. We evaluate the scalability on a large synthetic dataset by crawling users’ photos from Flickr, and a 12-week user study demonstrates the feasibility and effectiveness of our photo revisitation strategies.

Prospective memory function in late adulthood: affect at encoding and resource allocation costs.

Some studies have found that prospective memory (PM) cues which are emotionally valenced influence age effects in prospective remembering, but it remains unclear whether this effect reflects the operation of processes implemented at encoding or retrieval. In addition, none of the prior ageing studies of valence on PM function have examined potential costs of engaging in different valence conditions, or resource allocation trade-offs between the PM and the ongoing task. In the present study, younger, young-old and old-old adults completed a PM task in which the valence of the cues varied systematically (positive, negative or neutral) at encoding, but was kept constant (neutral) at retrieval. The results indicated that PM accuracy did not vary as a function of affect at encoding, and that this effect did not interact with age group. There was also no main or interaction effect of valence on PM reaction time in PM cue trials, indicating that valence costs across the three encoding conditions were equivalent. Old-old adults’ PM accuracy was reduced relative to both young-old and younger adults. Prospective remembering incurred dual-task costs for all three groups. Analyses of reaction time data suggested that for both young-old and old-old, these costs were greater, implying differential resource allocation cost trade-offs. However, when reaction time data were expressed as a proportional change that adjusted for the general slowing of the older adults, costs did not differ as a function of group.

Prospective memory failures in aviation: effects of cue salience, workload, and individual differences.

Prospective memory allows people to complete intended tasks in the future. Prospective memory failures, such as pilots forgetting to inform pattern traffic of their locations, can have fatal consequences. The present research examined the impact of system factors (memory cue salience and workload) and individual differences (pilot age, cognitive health, and expertise) on prospective memory for communication tasks in the cockpit. Pilots (N = 101) flew a Cessna 172 simulator at a non-towered aerodrome while maintaining communication with traffic and attending to flight parameters. Memory cue salience (the prominence of cues that signal an intended action) and workload were manipulated. Prospective memory was measured as radio call completion rates. Pilots' prospective memory was adversely affected by low-salience cues and high workload. An interaction of cue salience, pilots' age, and cognitive health reflected the effects of system and individual difference factors on prospective memory failures. For example, younger pilots with low levels of cognitive health completed 78% of the radio calls associated with low-salience memory cues, whereas older pilots with low cognitive health scores completed just 61% of similar radio calls. Our findings suggest that technologies designed to signal intended future tasks should target those tasks with inherently low-salience memory cues. In addition, increasing the salience of memory cues is most likely to benefit pilots with lower levels of cognitive health in high-workload conditions.

Sources of interference in item and associative recognition memory.

A powerful theoretical framework for exploring recognition memory is the global matching framework, in which a cue's memory strength reflects the similarity of the retrieval cues being matched against the contents of memory simultaneously. Contributions at retrieval can be categorized as matches and mismatches to the item and context cues, including the self match (match on item and context), item noise (match on context, mismatch on item), context noise (match on item, mismatch on context), and background noise (mismatch on item and context). We present a model that directly parameterizes the matches and mismatches to the item and context cues, which enables estimation of the magnitude of each interference contribution (item noise, context noise, and background noise). The model was fit within a hierarchical Bayesian framework to 10 recognition memory datasets that use manipulations of strength, list length, list strength, word frequency, study-test delay, and stimulus class in item and associative recognition. Estimates of the model parameters revealed at most a small contribution of item noise that varies by stimulus class, with virtually no item noise for single words and scenes. Despite the unpopularity of background noise in recognition memory models, background noise estimates dominated at retrieval across nearly all stimulus classes with the exception of high frequency words, which exhibited equivalent levels of context noise and background noise. These parameter estimates suggest that the majority of interference in recognition memory stems from experiences acquired before the learning episode.

Enhanced semantic priming in synesthetes independent of sensory binding.

Synesthesia is the phenomenon in which individuals experience unusual involuntary cross-modal pairings. The evidence to date suggests that synesthetes have access to advantageous item-specific memory cues linked to their synesthetic experience, but whether this emphasis on item-specific memory cues comes at the expense of semantic-level processing has not been unambiguously demonstrated. Here we found that synesthetes produce substantially greater semantic priming magnitudes, unrelated to their specific synesthetic experience. This effect, however, was moderated by whether the synesthetes were projectors (their synesthetic experience occurs in their representation of external space), or associators (their synesthetic experience occurs in their 'mind's eye'). That is, the greater a synesthetes's tendency to project their experience, the weaker their semantic priming when the task did not require them to semantically categorize the stimuli, whereas this trade-off was absent when the task did have that requirement.

Neural modeling of sequential inferences and learning over episodic memory

Episodic memory is a significant part of cognition for reasoning and decision making. Retrieval in episodic memory depends on the order relationships of memory items which provides flexibility in reasoning and inferences regarding sequential relations for spatio-temporal domain. However, it is still unclear how they are encoded and how they differ from representations in other types of memory like semantic or procedural memory. This paper presents a neural model of sequential representation and inferences on episodic memory. It contrasts with the common views on sequential representation in neural networks that instead of maintaining transitions between events to represent sequences, they are represented as patterns of activation profiles wherein similarity matching operations support inferences and reasoning. Using an extension of multi-channel multi-layered adaptive resonance theory (ART) network, it is shown how episodic memory can be formed and learnt so that the memory performance becomes dependent on the order and the interchange of memory cues. We present experiments as a proof of concepts to show that the model contrasts sequential representations in semantic memory with those in episodic memory and the model can exhibit transitive inferences consistent with human and animals data.

Metamemory ratings predict long-term changes in reactivated episodic memories.

Reactivation of long-term memory can render the memory item temporarily labile, offering an opportunity to modify it via behavioral or pharmacological intervention. Declarative memory reactivation is accompanied by a metamemory ability to subjectively assess the knowledge available concerning the target item (Feeling of knowing, FOK). We set out to examine whether FOK can predict the extent of change of long-term episodic memories by post-retrieval manipulations. To this end, participants watched a short movie and were immediately thereafter tested on their memory for it. A day later, they were reminded of that movie, and either immediately or 1 day later, were presented with a second movie. The reminder phase consisted of memory cues to which participants were asked to judge their FOK regarding the original movie. The memory performance of participants to whom new information was presented immediately after reactivating the original episode corresponded to the degree of FOK ratings upon reactivation such that the lower their FOK, the less their memory declined. In contrast, no relation was found between FOK and memory strength for those who learned new information 1 day after the reminder phase. Our findings suggest that the subjective accessibility of reactivated memories may determine the extent to which new information might modify those memories.

Supplemental Material for They Can Take a Hint: Older Adults Effectively Integrate Memory Cues During Recognition

Supplemental Material for They Can Take a Hint: Older Adults Effectively Integrate Memory Cues During Recognition

Improvement in Gait Performance after Training Based on Declarative Memory Cues in Patients with Parkinsons Disease: A Randomized Clinical Trial

Background: Deficits in automatic motor control, a typical feature of Parkinson’s disease (PD), contribute to progressive impairment in gait performance. The use of declarative memory cues in order to promote the engagement of attention and activation of the next movement in gait may minimize the consequences of lack of automatic control. Objectives: To verify the long-term efficiency of a new strategy based on declarative memory cues to improve the gait performance and independence in activities of daily living (ADL) in patients with PD. Design: Parallel prospective, single blind, randomized clinical trial. Setting: Brazil Parkinson Association. Participants: Forty-four patients with PD in stages 2-3 of disease evolution according to Hoehn and Yahr Classification. Interventions: The experimental training (ET) consisted of eight gait training sessions, twice a week, using the declarative memory cue strategy (DMCS). The control training (CT) consisted of a similar gait training without DMCS. Primary outcome measure: Gait performance in terms of speed and stride length. Secondary outcome measure: Independence in ADL according to Section II of the Unified Parkinson’s Disease Rating Scale. Randomization: Participants were randomized into a control group (CG), which performed the CT, and an experimental group (EG), which performed the ET, through blinded drawing of names. Statistical analysis: Gait performance and independence in ADL before, 2 and 60 days after the end of training were compared for CG and EG using RM-ANOVA. Results: RM-ANOVA revealed a significant improvement of the gait performance in terms of speed and stride length and independence in ADL, remained until 2 months after the end of training, exclusively for the EG after ET. Conclusion: Gait training associated to declarative memory cues promotes significant long-term improvements in gait performance and can be considered a new useful strategy to compensate the deficiency in automatic motor control of gait in PD patients.

Improved memory for reward cues following acute buprenorphine administration in humans

In rodents, there is abundant evidence for the involvement of the opioid system in the processing of reward cues, but this system has remained understudied in humans. In humans, the happy facial expression is a pivotal reward cue. Happy facial expressions activate the brain's reward system and are disregarded by subjects scoring high on depressive mood who are low in reward drive. We investigated whether a single 0.2mg administration of the mixed mu-opioid agonist/kappa-antagonist, buprenorphine, would influence short-term memory for happy, angry or fearful expressions relative to neutral faces. Healthy human subjects (n38) participated in a randomized placebo-controlled within-subject design, and performed an emotional face relocation task after administration of buprenorphine and placebo. We show that, compared to placebo, buprenorphine administration results in a significant improvement of memory for happy faces. Our data demonstrate that acute manipulation of the opioid system by buprenorphine increases short-term memory for social reward cues.

The relationship between event-based prospective memory and ongoing task performance in chimpanzees (Pan troglodytes).

Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates.

Effects of varied and constant environmental contexts on acquisition and retention.

Four experiments examined the decontextualization of memories, the stage of learning in which memories can be recalled in the absence of episodic memory cues. Face-name pairs were studied with video-recorded environmental contexts in the background, and after 5 practice trials, recall of names associated with faces was tested in the absence of the original video context cues. In Experiments 1, 2, and 3, five retrieval practice trials for a pair occurred either always with the original video context (constant context condition) or with a new context on each trial (varied context condition). Final recall was tested either on the same day (Experiments 3 and 4) or 2 days later (Experiments 1 and 2), and either the recall test context for each face was a new (never seen) video (Experiment 1) or there was no context shown at test (Experiments 2, 3, and 4). In the first 3 experiments, acquisition was better for the constant context condition, but on the final recall test, performance was better for pairs learned under varied context conditions. In Experiment 4, which used multiple study trials rather than multiple retrieval practices during acquisition, no differences were found between the constant and varied context conditions, either for acquisition or for final retention. The results show that acquisition trials given in varied contexts can result in decontextualized memories, but only when acquisition involves retrieval practice, rather than simple restudy trials. These results are consistent with the new theory of disuse, but not with the theory of encoding variability.

Glutaminase1 heterozygous mice show enhanced trace fear conditioning and Arc/Arg3.1 expression in hippocampus and cingulate cortex

Mice heterozygous for a mutation in the glutaminase (GLS1) gene (GLS1 HZ mice), with reduced glutamate recycling and release, display reduced hippocampal function as well as memory of contextual cues in a delay fear conditioning (FC) paradigm. Here, we asked whether this deficit reflects an inability to process contextual information or a selective alteration in salience attribution. In addition, we asked whether baseline and activity-induced hippocampal activity were diminished in GLS1 HZ mice. For this purpose, we manipulated the relative salience of the conditioned stimulus (CS) and contextual cues in FC tasks, and examined gene expression of the immediate early gene Arc (Arc/Arg3.1) in hippocampus and anterior cingulate cortex (ACC) following trace FC (tFC). The results indicate that GLS1 HZ mice succeed in processing contextual information when the salient CS is absent or less predictive. In addition, in the hippocampus-dependent tFC paradigm GLS1 HZ mice display enhanced CS learning. Furthermore, while baseline arc activation was reduced in GLS1 HZ mice in the hippocampus, in line with previous fMRI findings, it was enhanced in the hippocampus and anterior cingulate cortex following tFC. These findings suggest that GLS1 HZ mice have a pro-cognitive profile in the tFC paradigm, and this phenotype involves activation of both hippocampus and ACC.Taken together with previous work on the GLS1 HZ mouse, this study sheds light on the importance of glutamate transmission to memory processes that require the allocation of attentional resources, and extends our understanding of the underpinnings of attention deficits in SZ.